Paget's disease is a chronic condition that causes abnormal bone remodeling resulting in thickened and enlarged bones, and is most common in older adults. It is typically diagnosed based on elevated alkaline phosphatase levels and imaging showing bone changes, and treatment focuses on relieving symptoms like pain through bisphosphonates, diet, exercise or sometimes surgery. Proper management can help prevent complications like fractures and bone deformities associated with Paget's disease.